use constant LEVELS => {
   DEBUG     =>  0,
   INFO      =>  1,
   NOTICE    =>  2,
   NOTE      =>  2,
   WARNING   =>  3,
   ERROR     =>  4,
   ERR       =>  4,
   CRITICAL  =>  5,
   CRIT      =>  5,
   ALERT     =>  6,
   EMERGENCY =>  7,
   EMERG     =>  7,
}

BEGIN {
   for my $level (keys LEVELS) {
      no strict 'refs';
      my $sub = lc($level);
      *{"$sub"} = sub { my $self = shift; $self->_print($level, @_); };
   }
}